In the title complex, [Cu4Cl4(C58H52N2P4)]n, four CuII atoms are held together via two doubly bridging and two triply bridging chlorides, forming a stair-like Cu4Cl4 core having crystallographically imposed inversion symmetry, while the benzene-1,4-diamine ligand (with a crystallographic inversion center at the centroid) acts in a tetradentate coordination mode, bridging two adjacent Cu4Cl4 cores, resulting in a chain along the a-axis direction. One Cu atom has a distorted tetrahedral geometry, coordinated by one P atom, one μ2-Cl and two μ3-Cl atoms, while the second Cu atom adopts a trigonal geometry, coordinated by one P atom, one μ2-Cl and one μ3-Cl atoms